CRISPR-based metabolic engineering in non-model microorganisms

Non-model microorganisms possess unique and versatile metabolic characteristics, offering great opportunities as cell factories for biosynthesis of target products. However, lack of efficient genetic tools for pathway engineering represents a big challenge to unlock the full production potential of these microbes. Over the past years, CRISPR systems have been extensively developed and applied to domesticate non-model microorganisms. In this paper, we summarize the current significant advances in designing and constructing CRISPR-mediated genetic modification systems in non-model microorganisms, such as bacteria, fungi and cyanobacteria. We particularly put emphasis on reviewing some successful implementations in metabolic pathway engineering via CRISPR-based genome editing tools. Moreover, the current barriers and future perspectives on improving the editing efficiency of CRISPR systems in non-model microorganisms are also discussed.